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We have had great results cleaning copper wound strings by agitating them in a bath of Parson's ammonia. The ammonia acts as a bright dip and the soap cleans all the gunk out from between the coils. Tried on iron wounds, this process cleans the coils out, but does nothing about the rust. They sound better, but that is all. To do a bright dip on these wires, we used battery acid, sulfuric acid. It did clean up the rust, but was a rather nasty experiance., even out doors with heavy gloves.

Looking for alternatives, I was led to phosphoric acid, but that stuff sounds just too scarry. At the other end of the spectrum was a suggestion to employ citric acid. That sounds less threatening, though, I assume you could still burn yourself with a strong enough solution.

If you manage to get any wisdom from the old world, please pass it on.

I've had success with a wire brush bit in my drill. I mount the drill in the vise and carefully work the string along sideways, so the brush can get in between the windings. Soft metal brush. Brass I think.

Don't try slapping them on a concrete floor. I say a guy at a PTG convention do that once, so I tried it at home. (I know, don't try this at home, kids. I should have heard that little voice in my head) Anyway, I broke the becket coil off. So I don't do that anymore.

170 years? I think they might be do to be replaced. I'd definitely go with the first response you got.

Well if the strings are out you can try dry ice blasting. We use dry ice and we also use two types of soda blasting here at my shop. The fine baking soda is what you want to use if you are going that route on strings. You want to avoid the Maint XL size which we use to strip finishes

If you haven't ever heard of soda blasting it was developed to clean the Statue of Liberty during it's restoration. The process is like sand blasting but produces no heat, doesn't harm plated parts or glass.

You should really be consulting with someone who specializes in period instruments. Since you're in the UK, make a visit to Finchcocks.

I'm in touch with some of our top specialists but I would have thought rusty steel is rusty steel?

You are dealing with a true antique instrument. You should consult with people who do museum quality restoration before you start meddling around.... ESPECIALLY before considering abrasive blasting! Techniques that may be acceptable on a modern instrument may not be on a historical artifact, and vice versa.

You are dealing with a true antique instrument. You should consult with people who do museum quality restoration before you start meddling around....

I meet with them on a regular basis (one of whom works on Finchcocks' instruments did some lovely work on my square) and they're also at the end of an email. Don't worry, I'm no meddling fool - I just like fresh ideas. Still, if anyone wants to lend a skilled hand (paid) and are in London do PM me.

Looking for alternatives, I was led to phosphoric acid, but that stuff sounds just too scarry. At the other end of the spectrum was a suggestion to employ citric acid. That sounds less threatening, though, I assume you could still burn yourself with a strong enough solution.

**Do not use hydrofluoric acid under any circumstances. It can kill you after an exposure that causes no serious discomfort.

That's what I meant by scarry. I only mentioned it because it seems to be the industrial choice for this operation. I hope it didn't sound like I was suggesting its use. Acid baths, however, are the normal method to wash iron-oxide from the surface of steel.

Even if the wires are made bright by hand using a suede brush, I would still do a submersion cleaning in a surfactant. Parson's household ammonia would still be my choice. It has been our finding that the loss of tone in bass strings is more due to an accumulation of dirt inside the wrap, and between the coils. The packed matter prevents the wire from subdividing, and gives a tubby tone. Once cleaned, the wire has its flexibity back, and can produce the higher partials.

That's what I meant by scarry. I only mentioned it because it seems to be the industrial choice for this operation. I hope it didn't sound like I was suggesting its use. Acid baths, however, are the normal method to wash iron-oxide from the surface of steel.

Argh, I'm not all there today! I meant Hydrofluoric acid, exposure to which can cause cardiac arrest.

I read lately about the use of benzene for plain wire, to clean corrosion traces.

Renner send me by mistake a product used to fight rust on metal, it smell as some products used on the cloth to get rid of rust, so I suggest it may be some phosphorous (hydrofluoric) acid within (same smell on bleach agent for wood)

Agressive to glass probably the fumes are terrible for human ; I heard an horror story of an Africn man that find a job to wash the dishes from the planes (may be metal plates at those times some 10 years ago ?)

He did not new how much concentrated product to use in the hot water bath, put way too much, and smelled the fumes;Went to the hospital the same day and died 2 days later.

Edited by Olek (01/25/1306:19 AM)

_________________________
Professional of the profession.

I wish to add some kind and sensitive phrase but nothing comes to mind.!

The ammonia dip is counteracted by a dip in a weak vinigar solution (two glugs from a jug in five gallons of water.)

The vinegar solution is then washed out in a clean water dip.

This leaves me with a bundle of wet strings. There should be no acid or alkyline left, though I wonder about the chlorination in the water sometimes.

I first use compressed air to drive most of the moisture from the coils.

I have an aluminum pipe, about 7 feet long. Before I even start cleaning the wires, I put this pipe on a table and stick a hair dryer in one end an set it on LOW. By the time I am done cleaning the tube is quite warm along its entire length with warm air coming out the end. Before this warm air goes in but cool air comes out. It is important that the pipe not steal all the energy from the airflow.

The clean bundle of strings is then inserted into the tube. The warm, [u]NOT HOT[u], air will pull the last of moisture from the coils. If you hold an RH meter at the end of the pipe, you can watch the progress. When the reading approaches that of the unloaded tube, you are done.

We have done this for about 20 years. It was developed out of necessity back when the great bass string winder here in the US simply would not send you back strings that matched those you had sent in...always light. They even had a tag on the bundle that told you that" due to our long experience we reserve the right to modify blah, blah, blah." Talk about something that steals all the growl from a piano!

A cautionary note.a fellow tech used this method, but thought he would speed the process of drying up. So he coiled up the set and put them in a 300 degree oven. Temper, temper! He managed to anneal the cores. He said they stretched and snapped like licorice. I suspect he left them in there a long time, as in forgot them. Thats why I use the hair drier. If you cannot hold your hand in the airflow it is too hot. After all we are only trying to evaporate water.

There is a really great product I've used on things that can be soaked in it for getting rid of rust. Its called Evapo-Rust. Not sure if it effects copper, but it is all natural and no associated heavy fumes. It can be used over and over until th solution turns black. Parts need to be rinsed with water after and then dried quickly with wipes or hair dryer. This stuff is very thorough and works really well. I have salvaged rusty fine tooth files, saw blades and other tools with it after they were removed from a factory fire.

Frito, the rust can dull the tone a bit, increase the likelyhood of broken strings, and also incurr false beats if the rust is heavy and unevenly distributed along the speaking length of the string. Lots of old pianos out there with lightly rusted/pitted strings and the owners really can't tell the difference. Tuners and more professional musicians will pick up on the subtle differences.

There's nothing subtle about the tub-tub-tubbiness of my bass octave. I've another piano only just over 100 years old where 1/2 dozen notes are steel wound. Again the copper-wound that follow sing out beautifully, the steel wound - tub-tub-tubby.

Is there a UK equivalent to Evapo-Rust? (though perhaps I'd be happier with a soft brass brush and magnifying glass kinda like they do with old masters)

I've read on several guitar forums that they have been using ultrasonic cleaning tanks on their wound strings with great success. These are typically used for cleaning jewelry and other objects with fine features/crevices ect. They use isopropyl alcohol as the cleaning medium. Many of the users claim higher partials become more prominant and the string rings more clearly after cleaning.

I tried to find such Ultrasonic bath to clean agrafes and bass strings.

It is filled, I did not knew which liquid is used. Isopropyl is excellent as it is almost acetone, probably less acid

very certainly cleaning must be effective. but how to obtain a large enough bath for a low enough price ?I thought of using the ultrasonic parts that can be find in moisteners but they are not powerful enough - I tried to fulfill a tank with one US piece in it, and water (plastic tank) very little result.

Possibly some external company have the adequate baths ( I find one for glass beads blasting, just near my place)

Edited by Olek (01/27/1311:01 AM)

_________________________
Professional of the profession.

I wish to add some kind and sensitive phrase but nothing comes to mind.!

I was thinking that the strings could get pulled through the top of a tank in an arc. They typically only clean for a few minutes at most so a band of base strings could pprobably get pulled through a bath in under and hour.